When Wimbledon opens this week, rare pangs of nostalgia will set in. I don't pine for much of the past in sports. Free agency, the designated- hitter, baggy basketball shorts, professionalism at the Olympics, nightclub- worthy tennis dresses and NFL instant replay all appeal to me more than their predecessors.

But I miss Chris Evert and Martina Navratilova. None of today's athletes, male or female, can match what these two wrought as adversaries on the court and as friends off it. Nor, for that matter, can anyone from an earlier era.

A new book, "The Rivals: Chris Evert vs. Martina Navratilova, Their Epic Duels and Extraordinary Friendship" (Broadway publishing, $24.95) examines their relationship in greater detail than ever before. Author Johnette Howard unravels a lot of mythology about the two champions, presenting the reader with two fleshy, complicated personalities who still very much deserve their place on a pedestal.

Howard masterfully dissects the fixed images of the two, revealing the lovable vulnerability in the physically powerful and politically outspoken Navratilova and underscoring Evert's ferocious ambition, which was too often obscured by tributes to her conventional femininity.

I expected the most fascinating parts of the book to be about Navratilova, the defector, who came out as gay in 1981. But one of the most moving sections deals with Evert's fight to keep up with the increasingly dominant Navratilova in the mid-1980s. At that point, Evert could have retired gracefully, acknowledging that her day had passed.

"I know what people are saying, but I don't buy it -- I'm not quitting, " Evert says. "I'm not like (Bjorn) Borg, cutting all ties when I can't win the big one. I love the game too much."

But Navratilova unnerved her, and Howard takes the reader inside Evert's head, making her torment palpable. When Evert played, determination seeped out of her pores, but there's a difference between being tough and being fearless. To pursue Navratilova, Evert had to change her body, her game and her conservative mind-set. She couldn't play it safe, hanging on the baseline. Her metamorphosis is almost as exhilarating as the account of Navratilova's 1975 defection.

Navratilova, generally hailed as bravely stubborn, is recast in the book as a passionately free spirit, hungering to escape the confines of Communist Czechoslovakia. It's a revelation, now as much as ever, to see American values through Navratilova's eyes. She pursues gay rights with romantic idealism, expecting the best, holding this country to promises it hasn't resolved to keep.

Navratilova could have resented the whole Chrissie phenomenon, the way Evert traded on her apple-pie image. Likewise, Evert could have distanced herself from Navratilova, the rebel. They were both too big for that. If no other sports rivalry can match this one, it's because these two women, through their affection and respect for each other, transcended all manner of social boundaries.

They looked out for each other in ways that Muhammad Ali and Joe Frazier, Larry Bird and Magic Johnson, John McEnroe and Borg never did -- and never needed to. Evert traveled to the 1986 Federation Cup in Prague despite a bum knee, because she wanted to be alongside Navratilova when she returned to her homeland for the first time in 11 years. Six months later, Navratilova and then-girlfriend Judy Nelson invited a lonely Evert, nearing her divorce from John Lloyd, to their Aspen home for the holidays and introduced her to Andy Mill, who became her second husband.

It's too much to ask of today's athletes that they duplicate the grandeur of this rivalry. Navratilova and Evert came of age at an extraordinary time, during the Cold War, in the heart of the women's movement, just after the reign of Billie Jean King, who did a lot of dirty work for her descendants in women's tennis. Martina and Chris never had to compete against men to legitimize themselves or pose naked for Maxim. They epitomized sportsmanship during the ascension of trash talk, and offset the prevailing image of women in cutthroat competition -- Joan Collins and Linda Evans thrashing in a fountain on the set of the television show "Dynasty."

As the LPGA comes into its own, let's hope the new generation takes its cue from Evert vs. Navratilova and not Tonya Harding vs. Nancy Kerrigan. That could be tough in an era when the media reward obnoxiousness with extravagant attention, and intense competitors such as Jeff Kent and Terrell Owens allow their best instincts to dissolve into pettiness. Evert and Navratilova knew that they made each other better, and in realizing that, they elevated their sport. We may see harder serves and quicker feet as the game evolves, but we will never see anything more graceful.